BILLINGS, Mont. — Coal-bed methane industry representatives on Thursday asked federal regulators to loosen wildlife restrictions that shut down much of the industry's operations in Wyoming's Powder River Basin this spring.

During breeding periods for sage grouse, eagles and other wildlife, the federal Bureau of Land Management imposes monthslong shutdowns of coal-bed methane work to prevent disturbance of the birds' nests and mating grounds.

Researchers from the University of Montana say sage grouse populations in the Powder River Basin have suffered a sharp decline inside active coal-bed methane fields over the past decade.

As coal-bed methane, or natural gas, production shifted onto federal land during the past year, the restrictions meant to protect the birds came into play more often. That curtailed the drilling of new wells and prompted layoffs of some industry contractors.

In response, the Petroleum Association of Wyoming this week hosted a two-day "sage grouse workshop" in Casper involving coal-bed methane companies, state and federal regulatory agencies and independent researchers.

BLM officials would not comment on the request to modify its restrictions but agreed to work with the industry in the future.

"Nobody in industry is asking BLM to scratch what we have and reduce protections. It's just how can we do things more efficiently," association vice president Jason Begger said.

In the case of sage grouse, the drilling area closures last from March through mid-June and cover a two-mile radius around the bird's breeding grounds, or leks.

Offering an example of how those rules don't always make sense, Begger said that if a closed area is also bisected by a highway, it does little good to apply the restrictions to areas separated from the lek by the road.

BLM officials have said there has been no research to determine if the restrictions work.

But the possibility of relaxing the rules with sage grouse already on the decline was dismissed by Jill Morrison with the Powder River Basin Resource Council.

"What we're doing isn't very effective, and it sounds like this will make it worse," said Morrison, whose group has pushed for tighter controls on the industry. "The sage grouse is going over the brink. We're already going in the wrong direction and they just want to get there faster."

Wyoming BLM Associate State Director Don Simpson said he anticipated "a continued dialogue with industry and the various partners that are working together" to address sage grouse issues.

Another federal official, U.S. Fish and Wildlife Service field supervisor Brian Kelly, commended Begger's group for "taking the lead" in dealing with sage grouse problems.

"They realize there are major impacts on these species and they are declining as a result," Kelly said.